The present invention relates generally to a lock, and more particularly to an electronic lock.
As shown in FIGS. 1 and 2, an electronic lock of the prior art comprises a housing 1 which is fastened with a base 2 for containing a lock core 3, a large circular pad 4, a small circular pad 5, a retaining pillar 6, an elastic element 7, and an electromagnetic element 8. A handle shaft 9 is fastened pivotally with the housing 1 for mounting thereon the electromagnetic element 8. The handle shaft 9 is provided in the periphery thereof with a plurality of second engagement projections 91 corresponding to a first engagement projection 61 of the retaining pillar 6. The elastic element 7 is engaged at one end thereof with the second engagement projections 91. The handle shaft 9 is fastened with a handle 10 capable of actuating the handle shaft 9 to turn. The elastic element 7 is received at other end thereof in the center of the first engagement projection 61 of the retaining pillar 6. The retaining pillar 6 is provided at other end thereof with a retaining hole 62 for retaining a retaining projection 31 of the lock core 3. The retaining projection 31 is fitted into the large and the small circular pads 4 and 5. The lock core 3 is provided with a lock tongue 11. When the electromagnetic element 8 is connected with the power source, the small circular pad 5 and the large circular pad 4 are attached to the electromagnetic element 8 such that the retaining pillar 6 is actuated to remain in an action position. In the meantime, the second engagement projection 91 of the handle shaft 9 is completely engaged with the first engagement projection 61 of the retaining pillar 6, whereas the retaining hole 62 of the retaining pillar 6 is coupled with the retaining projection 31 of the lock core 3. As a result, the lock core 3 can be actuated to turn by the handle 10 via the handle shaft 9, the retaining pillar 6 and the retaining projection 31 of the lock core 3.
Such a prior art electronic lock as described above is defective in design in that it can be easily tampered with by an unauthorized person using a magnetic article to bring about an outward displacement of the large and the small circular pads, thereby resulting in the retaining pillar being activated to locate at the action position so as to cause the second engagement projection of the handle shaft to engage the first engagement projection of the retaining pillar. The lock core can be thus turned by the handle to unlock the electronic lock.
As shown in FIG. 3, another prior art electronic lock comprises a dish-shaped clutch magnetic collection seat which is a coil ring 2 mounted on the center shaft of an outer seat disk I for attracting the dish-shaped action piece 3 which is mounted on the actuation retainer 4. The actuation retainer 4 is provided with a retaining seat 5 and is engaged with a receiving seat 6 and a fitting ring 7. Located between the action piece 3 and the coil ring 2 is a spring 8 which is corresponding in location to another spring 9. The retaining seat 5 is fastened pivotally with an outer handle 13 in conjunction with a recessed wheel block 11 and a protruded wheel block 12. A square bolt 14 is joined with the receiving seat 6. When the magnetic action is at work, the action piece 3 forces the spring 8 to become attached to the coil ring 2. In the meantime, the actuation retainer 4 is moved to retain the retaining seat 5 so as to turn the outer handle 13. The motion is imparted to the receiving seat 6 to actuate the square bolt 14 to rotate. As a result, the tongue bolt 15 is unlocked. This prior art electronic lock can be also easily tampered with by an unauthorized person making use of a magnetic object having a greater magnetic force than the electronic lock.
The primary objective of the present invention is to provide an electronic lock which cannot be easily tampered with by an unauthorized person.
In keeping with the principle of the present invention, the foregoing objective of the present invention is attained by an electronic lock comprising a housing in which an electromagnetic element is disposed. The electromagnetic element is provided with a receiving slot receiving an elastic element which is fitted over a protruded pillar of an actuation block. The actuation block has an arresting ring which is confined to the side of the elastic element. The actuation block is provided with a fitting hole in which the connection shaft of an action piece is received. The action piece is thus located at the outer sides of the electromagnetic element and the actuation block. The connection shaft is provided at other end thereof with a fastening piece for fastening a handle. When the electromagnetic element is connected with the power source, the action piece is attracted to move inwards to urge the actuation block, which is thus forced to move inwards to compress the elastic element. The protruded pillar of the actuation block is then forced into the retaining block of the lock belly so as to control the unlocking of the lock tongue. At this time, the fitting hole of the actuation block is still engaged with the connection shaft. The door can be thus opened by turning the doorknob. When the electromagnetic element is disconnected from the power source, the actuation block is forced by the elastic force of the elastic element to move outward, thereby resulting in the separation of the protruded pillar from the retaining block. The action of the lock tongue thus cannot be controlled. All components of the electronic lock of the present invention must be engaged during the same inward action to unlock the electronic lock. The electronic lock of the present invention cannot be easily tampered with by an unauthorized person using a magnetic object having a magnetic force greater than the magnetic force of the electromagnetic element of the electronic lock.